Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215.
Department of Cell Biology, Harvard Medical School, Boston, MA 02215.
Proc Natl Acad Sci U S A. 2020 Sep 8;117(36):22204-22213. doi: 10.1073/pnas.2000643117. Epub 2020 Aug 26.
The peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is a transcriptional coactivator that controls expression of metabolic/energetic genes, programming cellular responses to nutrient and environmental adaptations such as fasting, cold, or exercise. Unlike other coactivators, PGC-1α contains protein domains involved in RNA regulation such as serine/arginine (SR) and RNA recognition motifs (RRMs). However, the RNA targets of PGC-1α and how they pertain to metabolism are unknown. To address this, we performed enhanced ultraviolet (UV) cross-linking and immunoprecipitation followed by sequencing (eCLIP-seq) in primary hepatocytes induced with glucagon. A large fraction of RNAs bound to PGC-1α were intronic sequences of genes involved in transcriptional, signaling, or metabolic function linked to glucagon and fasting responses, but were not the canonical direct transcriptional PGC-1α targets such as OXPHOS or gluconeogenic genes. Among the top-scoring RNA sequences bound to PGC-1α were , δ, , , , , , , and PGC-1α depletion decreased a fraction of these glucagon-induced messenger RNA (mRNA) transcript levels. Importantly, knockdown of several of these genes affected glucagon-dependent glucose production, a PGC-1α-regulated metabolic pathway. These studies show that PGC-1α binds to intronic RNA sequences, some of them controlling transcript levels associated with glucagon action.
过氧化物酶体增殖物激活受体γ共激活因子 1-α(PGC-1α)是一种转录共激活因子,它控制代谢/能量基因的表达,为细胞对营养和环境适应(如禁食、寒冷或运动)的反应编程。与其他共激活因子不同,PGC-1α 包含涉及 RNA 调节的蛋白质结构域,如丝氨酸/精氨酸(SR)和 RNA 识别基序(RRMs)。然而,PGC-1α 的 RNA 靶标及其与代谢的关系尚不清楚。为了解决这个问题,我们在用胰高血糖素诱导的原代肝细胞中进行了增强紫外线(UV)交联和免疫沉淀后测序(eCLIP-seq)。与 PGC-1α 结合的大量 RNA 是参与转录、信号转导或代谢功能的基因的内含子序列,与胰高血糖素和禁食反应有关,但不是经典的直接转录 PGC-1α 靶标,如 OXPHOS 或糖异生基因。与 PGC-1α 结合的得分最高的 RNA 序列中有 、δ、、、、、、和。PGC-1α 耗竭降低了这些胰高血糖素诱导的信使 RNA(mRNA)转录本水平的一部分。重要的是,这些基因中的几个的敲低影响了胰高血糖素依赖性葡萄糖产生,这是一种由 PGC-1α 调节的代谢途径。这些研究表明,PGC-1α 与内含子 RNA 序列结合,其中一些控制与胰高血糖素作用相关的转录本水平。